The present invention relates to a clutch-brake interlocking mechanism for use in vehicles such as tractors, as installed inside the transmission thereof.
To prevent vehicles from inadvertently moving rearward or forward in manipulating the transmission for speed changes on sloping roads, it is conventional practice to use a mechanism for interlocking the brake with the clutch. Such an interlocking mechanism is disclosed, for example, in Unexamined Japanese Utility Model Publication No. 103778/1987.
The interlocking mechanism disclosed in the publication comprises a first linkage connecting a clutch/brake pedal at the driver's seat to a tension clutch provided between an engine output shaft and a transmission input shaft, a second linkage connecting the first linkage to a brake, and a third linkage connecting the second linkage to a brake lever at the driver's seat. With the brake actuated by moving the brake lever, the clutch/brake pedal is stepped on to disengage the clutch from its engaged state, precluding the likelihood that both the clutch and the brake will be disengaged or released at the same time, whereby the vehicle can be prevented from moving rearward or forward inadvertently.
The disclosed mechanism nevertheless has the following drawback. The mechanism has a brake pedal in addition to the clutch/brake pedal, therefore comprises an increased number of components and requires a complex linkage for interconnecting these pedals, consequently making the vehicle itself more costly.
With the disclosed mechanism, the linkages interlocking the clutch and the brake are provided externally of the transmission and are accordingly complex and large-sized. This also results in an increased cost. The linkages, which are left exposed, are affected by soot and dust and become less durable.
Further with the disclosed mechanism, the clutch and the brake must be set for and adjusted to a half-engaged or half-actuated state, with the transmission installed in the vehicle, hence a poor work efficiency.
An object of the present invention, which has been accomplished to overcome the foregoing problems, is to provide a clutch-brake interlocking mechanism which is adapted to prevent both the clutch and the brake from becoming disengaged or released at the same time and which is inexpensive and highly durable and has a simple construction permitting facilitated adjustment of the clutch to the half-engaged state.